The present invention generally relates to apparatus and methods for forming first and second, continuous, independent, extrudates, and particularly to apparatus and methods for simultaneously forming two dough sheets from a single cooker extruder for the preparation of a snack product by conventional deep fat frying.
One type of snack product which has gained wide market acceptance is the "puffed" snack product. In certain methods of preparation, a cooked farinaceous dough is formed into a single continuous dough sheet. This dough sheet is then run through a piece forming apparatus which includes an opposed pair of rollers at least one of which has depressions which stamp out the desired shape and size pieces from the dough sheet. After formation of the dough pieces, the pieces are dried under controlled conditions from a moisture content of about 18% down to a moisture content of between 10% and 15% to form a half product or pellet. The moisture content of the half product is sufficiently low to exhibit extended shelf stability. The snack product is prepared from the half product by conventional deep fat frying. The frying of the half product generates steam volumes inside of the half product to puff the half product resulting in a light, puffed snack product having surface corrugations.
The sale of snack food products is a highly competitive business. The novelty of snack food products decline rapidly, as new and different types of snack foods are introduced to maintain or increase market share. Puffed snack products can be varied in various ways such as by changing the shapes, sizes, and surface corrugations of the pieces or by changing the composition of the dough from which the half products are prepared. Another variation is to have the puffed snack product of a hollow structure, with the hollow configuration resulting from the fabrication of the half products from a two-layer laminated dough sheet. One method of forming a laminated dough sheet is to fold a single continuous dough sheet into a two-plied dough sheet as set forth in U.S. application No. 699,039 filed May 13, 1991, now U.S. Pat. No. 5,092,757.
The continuous dough sheet is often formed by passing a plurality (such as 4) of spaced ropes of dough between sheet pressing rollers. The spaced ropes of dough are extruded from a cooker extruder onto a conveyor which delivers the ropes of dough to the sheet pressing rollers. Generally, the dough ropes are formed by forcing the dough through a die plate including extrusion apertures. The formation of the dough sheet from a plurality of spaced ropes rather than passing a single amount of dough between the sheet pressing rollers forms a more uniform sheet resulting in more uniform half product pieces and more uniform puffed snack pieces. Additionally, the formation of the dough sheet from a plurality of spaced ropes rather than passing a single amount of dough between the sheet pressing rollers better dissipates heat along the sheet pressing rollers. However, the formation of such a dough sheet continuously from a plurality of dough ropes presents many problems. In particular, it should be appreciated that the ropes of dough have to be generally uniformly spaced on the conveyor and into the sheet pressing rollers. Further, a common problem is that the dough ropes will break causing the ropes of dough to fall on the floor and/or become entangled with each other. Further, the cooker extruder is a relatively expensive piece of equipment which has the capacity to supply ropes of dough for more than one sheet and in fact the consistency of the dough produced by the cooker extruder may in fact increase with the production of dough for more than one sheet from the same cooker extruder. However, it can be appreciated that additional problems arise from attempting to simultaneously extrude dough ropes for two dough sheets. Particularly, in addition to preventing consistent production for one sheet, breakage of one or more dough ropes for one of the sheets may detrimentally effect the consistent production of the other sheet, for example, the ropes of dough for one sheet becoming entangled in the ropes of dough for the other sheet. Further, factors such as unequal pressure drop through the respective die channels, the length of the channels, and the like affect the uniformity and consistency of the dough ropes which in turn affect the uniformity and consistency of the dough sheet, the half products, and the puffed snack products.
Accordingly, it is an object of the present invention to provide novel apparatus and methods for the simultaneous formation of two continuous dough sheets from a single cooker extruder.
Another object of the present invention is to provide such novel apparatus and methods where the ropes of dough extruded from the cooker extruder are directed at a non-parallel angle to reduce operational failure of the formation of one sheet from detrimentally affecting the formation of the other sheet.
Yet another object of the present invention is to provide such novel apparatus and methods where the ropes of dough are uniformally and consistently extruded.